HGV heavy-goods-vehicle-hgv-inspection-manual- Je comprend pas, mais....


Emergency Brake and Air Line Connections:
 Ensure that the air reservoirs on the drawing vehicle are fully charged.
 With the vehicle parking brake on and the trailer parking brake off, ask the driver to disconnect the service (yellow) and
emergency (red) brake lines.
 Check, on vehicles and trailers fitted with "C" type couplings, that the coupling in the service (yellow) line - either fitted to the
trailer or in the line itself - is fitted with an operating adaptor which can open the ***self sealing coupling*** in the connector from the
drawing vehicle.
 Check that the operating adaptor lifts the indicator on the test coupling by the correct amount. The waisted portion (coloured
section) of the indicator must be exposed, but no more than this. This does not include additional couplings which may be used
on trailers such as extendable types.
 Check that any brake line on the drawing vehicle is not fitted with a manual shut-off tap. Additional taps fitted to extendable
trailers are not included in this inspection.

page 82 3. Operating adaptor, to open **self sealing coupling**:
a. not fitted in service (yellow) line.
*b. produces incorrect amount**** of lift. ***
page 81 Provided ***self sealing couplings*** are used on the tractor couplings it does not matter whether the air adaptor couplings are the
conventional way or reversed.

From Althea's ref prosol.co.uk/product/brake-airline-valve-lift-gauge/ On the Service Line there will be a Female C coupling and a valve lifter (to open the self sealing valve).

Canadian Air ispumpedbythecompressor (1) tothe wet reservoir (5),
which isprotectedfrom overpressurization byasafetyvalve
(4).Thegovernor (2) controls thepressurein thereservoir
tothebottom of thefootvalve(31).Thedriverpushes the
footvalvetreadledown andairpressure flows tothefront
andrearbrakechambers (32 & 11).Thebrakechamberpush
rods movetheslackadjusters.Theslackadjusters rotate
theS-cams, forcingthebrakeshoesagainst thedrums.This
causes friction that stops the wheels.Thedriver releases
thefootvalvetreadleandtheair in thebrakechambers is
allowedtoexhaust through thefootvalve, releasingthe
brakes.
Thefollowingexplains theadditional componentsofabasic
airbrakesystem. Othervalves which are necessarytoensure
smooth andefficientoperationsare not includedin this
simpledrawing.They willbediscussedlater in the manual.
Note: An airdryer (3) hasbeen addedtoreducetheamount
of moisturein thesystem.
One-wayCheck Valve
In thediagram below, tworeservoirsareshown (5)(10).To
preventair from flowingbackwards in thesystem toward
thecompressor,aone-waycheckvalve(7) is installed
between thereservoirs.Thisvalveallows theair to flow in
onedirection only.Thevalveis springloaded.Pressureat
theinlet sideovercomes thespringpressure****andlifts the
checkvalveball,ordisc,off its seat*****. Airpasses through the
valvetotheoutlet.When pressureat theoutletbecomes
greater than at theinlet - together with thespringpressure
- thecheckdeviceseats,preventingair from flowingback

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Note added at 1 day 1 hr (2023-04-25 21:32:13 GMT)
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https://assets.publishing.service.gov.uk/government/uploads/...




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Note added at 1 day 1 hr (2023-04-25 21:35:40 GMT)
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As stated by others, the O rings in Polish are probably not involved, different systems to stop BACK FLOW, and so on, or reversed lines https://www2.gnb.ca/content/dam/gnb/Departments/ps-sp/pdf/Pu...